1,219 research outputs found
The Extreme Hosts of Extreme Supernovae
We use GALEX ultraviolet (UV) and optical integrated photometry of the hosts of 17 luminous supernovae (LSNe, having peak M_V 100 M_☉), by appearing in low-SFR hosts, are potential tests for theories of the initial mass function that limit the maximum mass of a star based on the SFR
Environmental safety of entomopathogenic nematodes – Effects on abundance, diversity and community structure of non-target beetles in a forest ecosystem
The large pine weevil, Hylobius abietis, is a serious threat to reforestation in Europe that necessitates routine
use of chemical insecticides. Application of entomopathogenic nematodes (EPN) to the coniferous
tree stumps in which weevils breed has the potential to reduce the use of chemical pesticides. During
field trials to assess the efficacy of nematodes against pine weevil, non-target beetles were also identified
and quantified on 10 sites (14 trials). Nematodes were applied to stumps between June and July. Emergence
traps captured beetles exiting from nematode-treated and untreated control stumps. Four trials
were monitored in the months immediately following nematode application and ten were monitored
the year after nematode application.
A total of 65 species of non-target beetles were recovered, including 11 saproxylic species. We found no
evidence of an effect of applied EPN on non-target beetle species richness, abundance, species richness
per individual collected, or Shannon’s entropy (H’) either immediately or a year after nematode application,
when more wood-specialists were recorded. As expected, there were marked differences between
sites and/or tree species in the populations of non-target beetles recovered.
These results indicate that when EPN are applied in a forest ecosystem to suppress H. abietis populations,
the risk to non-target coleopteran populations must be considered negligible
Outcomes of 23-gauge pars plana vitrectomy in combined scleral buckling and vitrectomy for complex rhegmatogenous retinal detachments
Rhegmatogenous retinal detachments associated with proliferative vitreoretinopathy, giant retinal tears, ocular trauma, proliferative diabetic retinopathy, or necrotizing retinitis are considered more complex than those without these factors. The aim of the current review is to address the surgical outcomes and complications of 23-gauge pars plana vitrectomy with scleral buckling (23GPPV/SB) for repair of these complex retinal detachments. This retrospective study involved 54 eyes of 53 patients who underwent 23GPPV/SB between July 2007 and September 2009. Preoperative diagnosis, surgical technique, preoperative and postoperative visual acuities, intraoperative and postoperative complications, and anatomic reattachment rates were examined. Fifty-four eyes of 53 patients were reviewed in this study and indications for surgery varied. Mean logarithm of the minimal angle of resolution (logMAR) pre- and post-operative visual acuities were 1.166 (20/293) and 0.780 (20/120), respectively, which led to a statistically significant improvement in logMAR (P=0.0165). Single operation and final reattachment rates were 87% (47 of 54 eyes) and 100%, respectively. Postoperative complications included choroidal effusion/hemorrhage (14.8%, 8 of 54 eyes) and vitreous hemorrhage (11.1%, 6 of 54 eyes). Other more infrequent complications included hyphema (9.3%, 5 of 54 eyes), hypotony (5.6%, 3 of 54 eyes) and ocular hypertension > 35 mmHg (3.7%, 2 of 54 eyes). A total of 31.5% (17 of 54 eyes) of patients had a complication in the postoperative time period, but 58.8% of these resolved spontaneously without requiring an intervention. 23GPPV/SB may be considered for complex retinal detachment repair with good anatomic reattachment rates, but with relatively high complication rates
Vortex pairing in two-dimensional Bose gases
Recent experiments on ultracold Bose gases in two dimensions have provided
evidence for the existence of the Berezinskii-Kosterlitz-Thouless (BKT) phase
via analysis of the interference between two independent systems. In this work
we study the two-dimensional quantum degenerate Bose gas at finite temperature
using the projected Gross-Pitaevskii equation classical field method. While
this describes the highly occupied modes of the gas below a momentum cutoff, we
have developed a method to incorporate the higher momentum states in our model.
We concentrate on finite-sized homogeneous systems in order to simplify the
analysis of the vortex pairing. We determine the dependence of the condensate
fraction on temperature and compare this to the calculated superfluid fraction.
By measuring the first order correlation function we determine the boundary of
the Bose-Einstein condensate and BKT phases, and find it is consistent with the
superfluid fraction decreasing to zero. We reveal the characteristic unbinding
of vortex pairs above the BKT transition via a coarse-graining procedure.
Finally, we model the procedure used in experiments to infer system
correlations [Hadzibabic et al., Nature 441, 1118 (2006)], and quantify its
level of agreement with directly calculated in situ correlation functions.Comment: published versio
United States Patent Application Publication
A multiple robot control architecture including a plurality of robotic agricultural machines including a first and second robotic agricultural machine. Each robotic agricultural machine including at least one controller configured to implement a plurality of finite state machines Within an individual robot control architecture (IRCA) and a global information module (GIM) communicatively coupled to the IRCA. The GIMs of the first and second robotic agricultural machines being configured to cooperate to cause said first robotic agricultural machine and said second agricultural machine to perform at least one agricultural task
Control Architecture For Multi-Robot System
A multiple robot control architecture including a plurality of robotic agricultural machines including a first and second robotic agricultural machine. Each robotic agricultural machine including at least one controller configured to implement a plurality of finite state machines within an individual robot control architecture (IRCA) and a global information module (GIM) communicatively coupled to the IRCA. The GIMs of the first and second robotic agricultural machines being configured to cooperate to cause said first robotic agricultural machine and said second agricultural machine to perform at least one agricultural task
Alternative fidelity measure for quantum states
We propose an alternative fidelity measure (namely, a measure of the degree
of similarity) between quantum states and benchmark it against a number of
properties of the standard Uhlmann-Jozsa fidelity. This measure is a simple
function of the linear entropy and the Hilbert-Schmidt inner product between
the given states and is thus, in comparison, not as computationally demanding.
It also features several remarkable properties such as being jointly concave
and satisfying all of "Jozsa's axioms". The trade-off, however, is that it is
supermultiplicative and does not behave monotonically under quantum operations.
In addition, new metrics for the space of density matrices are identified and
the joint concavity of the Uhlmann-Jozsa fidelity for qubit states is
established.Comment: 12 pages, 3 figures. v2 includes minor changes, new references and
new numerical results (Sec. IV
Qualitative inquiry with persons with obesity about weight management in primary care and referrals
IntroductionReferrals to evidence-based weight management in the community-commercial sector are aligned with clinical recommendations but underutilized.MethodsThis qualitative study explored patients’ perceptions and expectations about obesity treatment in primary care and referral to community-commercial sector programs. Individual semi-structured interviews were conducted with a sample of US persons with obesity via telephone. Audiotape transcripts, interviewer notes, and independent review of data by two investigators allowed for data and investigator triangulation. Transcripts were analyzed using thematic analysis.ResultsData saturation was reached with 30 participants who had a mean age of 41.6 years (SD 9.4), 37% male, 20% Black/African American and 17% Hispanic, 57% college educated, and 50% were employed full-time. Three primary themes emerged: (1) frustration with weight management in primary care; (2) patients expect providers to be better informed of and offer treatment options; and (3) opportunities and challenges with referrals to community-commercial programs.DiscussionPatients expect that providers offer personalized treatment options and referrals to effective community-commercial programs are an acceptable option. If patient-level data are shared between clinical and community entities to facilitate referrals, then privacy and security issues need attention. Future research is needed to determine feasibility of implementing clinical to community-commercial referrals for obesity treatment in the United States
The high-speed X-ray camera on AXIS
AXIS is a Probe-class mission concept that will provide high-throughput,
high-spatial-resolution X-ray spectral imaging, enabling transformative studies
of high-energy astrophysical phenomena. To take advantage of the advanced
optics and avoid photon pile-up, the AXIS focal plane requires detectors with
readout rates at least 20 times faster than previous soft X-ray imaging
spectrometers flying aboard missions such as Chandra and Suzaku, while
retaining the low noise, excellent spectral performance, and low power
requirements of those instruments. We present the design of the AXIS high-speed
X-ray camera, which baselines large-format MIT Lincoln Laboratory CCDs
employing low-noise pJFET output amplifiers and a single-layer polysilicon gate
structure that allows fast, low-power clocking. These detectors are combined
with an integrated high-speed, low-noise ASIC readout chip from Stanford
University that provides better performance than conventional discrete
solutions at a fraction of their power consumption and footprint. Our
complementary front-end electronics concept employs state of the art digital
video waveform capture and advanced signal processing to deliver low noise at
high speed. We review the current performance of this technology, highlighting
recent improvements on prototype devices that achieve excellent noise
characteristics at the required readout rate. We present measurements of the
CCD spectral response across the AXIS energy band, augmenting lab measurements
with detector simulations that help us understand sources of charge loss and
evaluate the quality of the CCD backside passivation technique. We show that
our technology is on a path that will meet our requirements and enable AXIS to
achieve world-class science.Comment: 17 pages, 11 figures, submitted to Proceedings of SPIE Optics +
Photonics 202
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